After the annexation of the Crimean peninsula by the Russian Federation, the construction of the Kerch bridge crossing, which has not been coordinated with Ukraine, has been started, which in the near future may lead to the destruction of the unique flora and fauna of the Black and Azov Seas. The results of the Kerch Strait Bridge construction consequences for the environment are presented. The main sources of data were the materials of remote sensing (RS), National Aeronautics and Space Administration (NASA), European Space Agency (ESA), US Geological Survey (USGS), literary sources, as well as the results of Tuzla Island survey carried out before the beginning of construction. The data regarding ecologic and hydrologic situation caused by the Kerch Strait Bridge construction were processed for the period between 2014 and 2017. An expert evaluation was conducted to determine the damage caused to Ukraine as a result of the construction of the Kerch Bridge, as well as the gathering of evidences upon violations of Ukrainian and international legislation for further consideration in international courts. The conclusion about significant changes in the water regime of the Kerch Strait and the entire Sea of Azov was made.